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-rw-r--r--src/cmd/internal/obj/sym.go426
1 files changed, 426 insertions, 0 deletions
diff --git a/src/cmd/internal/obj/sym.go b/src/cmd/internal/obj/sym.go
new file mode 100644
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+++ b/src/cmd/internal/obj/sym.go
@@ -0,0 +1,426 @@
+// Derived from Inferno utils/6l/obj.c and utils/6l/span.c
+// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/obj.c
+// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/span.c
+//
+// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
+// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+// Portions Copyright © 1997-1999 Vita Nuova Limited
+// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+// Portions Copyright © 2004,2006 Bruce Ellis
+// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+// Portions Copyright © 2009 The Go Authors. All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package obj
+
+import (
+ "cmd/internal/goobj"
+ "cmd/internal/objabi"
+ "fmt"
+ "log"
+ "math"
+ "sort"
+ "strings"
+)
+
+func Linknew(arch *LinkArch) *Link {
+ ctxt := new(Link)
+ ctxt.hash = make(map[string]*LSym)
+ ctxt.funchash = make(map[string]*LSym)
+ ctxt.statichash = make(map[string]*LSym)
+ ctxt.Arch = arch
+ ctxt.Pathname = objabi.WorkingDir()
+
+ if err := ctxt.Headtype.Set(objabi.GOOS); err != nil {
+ log.Fatalf("unknown goos %s", objabi.GOOS)
+ }
+
+ ctxt.Flag_optimize = true
+ return ctxt
+}
+
+// LookupDerived looks up or creates the symbol with name name derived from symbol s.
+// The resulting symbol will be static iff s is.
+func (ctxt *Link) LookupDerived(s *LSym, name string) *LSym {
+ if s.Static() {
+ return ctxt.LookupStatic(name)
+ }
+ return ctxt.Lookup(name)
+}
+
+// LookupStatic looks up the static symbol with name name.
+// If it does not exist, it creates it.
+func (ctxt *Link) LookupStatic(name string) *LSym {
+ s := ctxt.statichash[name]
+ if s == nil {
+ s = &LSym{Name: name, Attribute: AttrStatic}
+ ctxt.statichash[name] = s
+ }
+ return s
+}
+
+// LookupABI looks up a symbol with the given ABI.
+// If it does not exist, it creates it.
+func (ctxt *Link) LookupABI(name string, abi ABI) *LSym {
+ return ctxt.LookupABIInit(name, abi, nil)
+}
+
+// LookupABI looks up a symbol with the given ABI.
+// If it does not exist, it creates it and
+// passes it to init for one-time initialization.
+func (ctxt *Link) LookupABIInit(name string, abi ABI, init func(s *LSym)) *LSym {
+ var hash map[string]*LSym
+ switch abi {
+ case ABI0:
+ hash = ctxt.hash
+ case ABIInternal:
+ hash = ctxt.funchash
+ default:
+ panic("unknown ABI")
+ }
+
+ ctxt.hashmu.Lock()
+ s := hash[name]
+ if s == nil {
+ s = &LSym{Name: name}
+ s.SetABI(abi)
+ hash[name] = s
+ if init != nil {
+ init(s)
+ }
+ }
+ ctxt.hashmu.Unlock()
+ return s
+}
+
+// Lookup looks up the symbol with name name.
+// If it does not exist, it creates it.
+func (ctxt *Link) Lookup(name string) *LSym {
+ return ctxt.LookupInit(name, nil)
+}
+
+// LookupInit looks up the symbol with name name.
+// If it does not exist, it creates it and
+// passes it to init for one-time initialization.
+func (ctxt *Link) LookupInit(name string, init func(s *LSym)) *LSym {
+ ctxt.hashmu.Lock()
+ s := ctxt.hash[name]
+ if s == nil {
+ s = &LSym{Name: name}
+ ctxt.hash[name] = s
+ if init != nil {
+ init(s)
+ }
+ }
+ ctxt.hashmu.Unlock()
+ return s
+}
+
+func (ctxt *Link) Float32Sym(f float32) *LSym {
+ i := math.Float32bits(f)
+ name := fmt.Sprintf("$f32.%08x", i)
+ return ctxt.LookupInit(name, func(s *LSym) {
+ s.Size = 4
+ s.WriteFloat32(ctxt, 0, f)
+ s.Type = objabi.SRODATA
+ s.Set(AttrLocal, true)
+ s.Set(AttrContentAddressable, true)
+ ctxt.constSyms = append(ctxt.constSyms, s)
+ })
+}
+
+func (ctxt *Link) Float64Sym(f float64) *LSym {
+ i := math.Float64bits(f)
+ name := fmt.Sprintf("$f64.%016x", i)
+ return ctxt.LookupInit(name, func(s *LSym) {
+ s.Size = 8
+ s.WriteFloat64(ctxt, 0, f)
+ s.Type = objabi.SRODATA
+ s.Set(AttrLocal, true)
+ s.Set(AttrContentAddressable, true)
+ ctxt.constSyms = append(ctxt.constSyms, s)
+ })
+}
+
+func (ctxt *Link) Int64Sym(i int64) *LSym {
+ name := fmt.Sprintf("$i64.%016x", uint64(i))
+ return ctxt.LookupInit(name, func(s *LSym) {
+ s.Size = 8
+ s.WriteInt(ctxt, 0, 8, i)
+ s.Type = objabi.SRODATA
+ s.Set(AttrLocal, true)
+ s.Set(AttrContentAddressable, true)
+ ctxt.constSyms = append(ctxt.constSyms, s)
+ })
+}
+
+// Assign index to symbols.
+// asm is set to true if this is called by the assembler (i.e. not the compiler),
+// in which case all the symbols are non-package (for now).
+func (ctxt *Link) NumberSyms() {
+ if ctxt.Headtype == objabi.Haix {
+ // Data must be sorted to keep a constant order in TOC symbols.
+ // As they are created during Progedit, two symbols can be switched between
+ // two different compilations. Therefore, BuildID will be different.
+ // TODO: find a better place and optimize to only sort TOC symbols
+ sort.Slice(ctxt.Data, func(i, j int) bool {
+ return ctxt.Data[i].Name < ctxt.Data[j].Name
+ })
+ }
+
+ // Constant symbols are created late in the concurrent phase. Sort them
+ // to ensure a deterministic order.
+ sort.Slice(ctxt.constSyms, func(i, j int) bool {
+ return ctxt.constSyms[i].Name < ctxt.constSyms[j].Name
+ })
+ ctxt.Data = append(ctxt.Data, ctxt.constSyms...)
+ ctxt.constSyms = nil
+
+ ctxt.pkgIdx = make(map[string]int32)
+ ctxt.defs = []*LSym{}
+ ctxt.hashed64defs = []*LSym{}
+ ctxt.hasheddefs = []*LSym{}
+ ctxt.nonpkgdefs = []*LSym{}
+
+ var idx, hashedidx, hashed64idx, nonpkgidx int32
+ ctxt.traverseSyms(traverseDefs, func(s *LSym) {
+ // if Pkgpath is unknown, cannot hash symbols with relocations, as it
+ // may reference named symbols whose names are not fully expanded.
+ if s.ContentAddressable() && (ctxt.Pkgpath != "" || len(s.R) == 0) {
+ if s.Size <= 8 && len(s.R) == 0 && !strings.HasPrefix(s.Name, "type.") {
+ // We can use short hash only for symbols without relocations.
+ // Don't use short hash for type symbols, as they need special handling.
+ s.PkgIdx = goobj.PkgIdxHashed64
+ s.SymIdx = hashed64idx
+ if hashed64idx != int32(len(ctxt.hashed64defs)) {
+ panic("bad index")
+ }
+ ctxt.hashed64defs = append(ctxt.hashed64defs, s)
+ hashed64idx++
+ } else {
+ s.PkgIdx = goobj.PkgIdxHashed
+ s.SymIdx = hashedidx
+ if hashedidx != int32(len(ctxt.hasheddefs)) {
+ panic("bad index")
+ }
+ ctxt.hasheddefs = append(ctxt.hasheddefs, s)
+ hashedidx++
+ }
+ } else if isNonPkgSym(ctxt, s) {
+ s.PkgIdx = goobj.PkgIdxNone
+ s.SymIdx = nonpkgidx
+ if nonpkgidx != int32(len(ctxt.nonpkgdefs)) {
+ panic("bad index")
+ }
+ ctxt.nonpkgdefs = append(ctxt.nonpkgdefs, s)
+ nonpkgidx++
+ } else {
+ s.PkgIdx = goobj.PkgIdxSelf
+ s.SymIdx = idx
+ if idx != int32(len(ctxt.defs)) {
+ panic("bad index")
+ }
+ ctxt.defs = append(ctxt.defs, s)
+ idx++
+ }
+ s.Set(AttrIndexed, true)
+ })
+
+ ipkg := int32(1) // 0 is invalid index
+ nonpkgdef := nonpkgidx
+ ctxt.traverseSyms(traverseRefs|traverseAux, func(rs *LSym) {
+ if rs.PkgIdx != goobj.PkgIdxInvalid {
+ return
+ }
+ if !ctxt.Flag_linkshared {
+ // Assign special index for builtin symbols.
+ // Don't do it when linking against shared libraries, as the runtime
+ // may be in a different library.
+ if i := goobj.BuiltinIdx(rs.Name, int(rs.ABI())); i != -1 {
+ rs.PkgIdx = goobj.PkgIdxBuiltin
+ rs.SymIdx = int32(i)
+ rs.Set(AttrIndexed, true)
+ return
+ }
+ }
+ pkg := rs.Pkg
+ if rs.ContentAddressable() {
+ // for now, only support content-addressable symbols that are always locally defined.
+ panic("hashed refs unsupported for now")
+ }
+ if pkg == "" || pkg == "\"\"" || pkg == "_" || !rs.Indexed() {
+ rs.PkgIdx = goobj.PkgIdxNone
+ rs.SymIdx = nonpkgidx
+ rs.Set(AttrIndexed, true)
+ if nonpkgidx != nonpkgdef+int32(len(ctxt.nonpkgrefs)) {
+ panic("bad index")
+ }
+ ctxt.nonpkgrefs = append(ctxt.nonpkgrefs, rs)
+ nonpkgidx++
+ return
+ }
+ if k, ok := ctxt.pkgIdx[pkg]; ok {
+ rs.PkgIdx = k
+ return
+ }
+ rs.PkgIdx = ipkg
+ ctxt.pkgIdx[pkg] = ipkg
+ ipkg++
+ })
+}
+
+// Returns whether s is a non-package symbol, which needs to be referenced
+// by name instead of by index.
+func isNonPkgSym(ctxt *Link, s *LSym) bool {
+ if ctxt.IsAsm && !s.Static() {
+ // asm symbols are referenced by name only, except static symbols
+ // which are file-local and can be referenced by index.
+ return true
+ }
+ if ctxt.Flag_linkshared {
+ // The referenced symbol may be in a different shared library so
+ // the linker cannot see its index.
+ return true
+ }
+ if s.Pkg == "_" {
+ // The frontend uses package "_" to mark symbols that should not
+ // be referenced by index, e.g. linkname'd symbols.
+ return true
+ }
+ if s.DuplicateOK() {
+ // Dupok symbol needs to be dedup'd by name.
+ return true
+ }
+ return false
+}
+
+// StaticNamePref is the prefix the front end applies to static temporary
+// variables. When turned into LSyms, these can be tagged as static so
+// as to avoid inserting them into the linker's name lookup tables.
+const StaticNamePref = ".stmp_"
+
+type traverseFlag uint32
+
+const (
+ traverseDefs traverseFlag = 1 << iota
+ traverseRefs
+ traverseAux
+
+ traverseAll = traverseDefs | traverseRefs | traverseAux
+)
+
+// Traverse symbols based on flag, call fn for each symbol.
+func (ctxt *Link) traverseSyms(flag traverseFlag, fn func(*LSym)) {
+ lists := [][]*LSym{ctxt.Text, ctxt.Data, ctxt.ABIAliases}
+ for _, list := range lists {
+ for _, s := range list {
+ if flag&traverseDefs != 0 {
+ fn(s)
+ }
+ if flag&traverseRefs != 0 {
+ for _, r := range s.R {
+ if r.Sym != nil {
+ fn(r.Sym)
+ }
+ }
+ }
+ if flag&traverseAux != 0 {
+ if s.Gotype != nil {
+ fn(s.Gotype)
+ }
+ if s.Type == objabi.STEXT {
+ f := func(parent *LSym, aux *LSym) {
+ fn(aux)
+ }
+ ctxt.traverseFuncAux(flag, s, f)
+ }
+ }
+ }
+ }
+}
+
+func (ctxt *Link) traverseFuncAux(flag traverseFlag, fsym *LSym, fn func(parent *LSym, aux *LSym)) {
+ fninfo := fsym.Func()
+ pc := &fninfo.Pcln
+ if flag&traverseAux == 0 {
+ // NB: should it become necessary to walk aux sym reloc references
+ // without walking the aux syms themselves, this can be changed.
+ panic("should not be here")
+ }
+ for _, d := range pc.Funcdata {
+ if d != nil {
+ fn(fsym, d)
+ }
+ }
+ files := ctxt.PosTable.FileTable()
+ usedFiles := make([]goobj.CUFileIndex, 0, len(pc.UsedFiles))
+ for f := range pc.UsedFiles {
+ usedFiles = append(usedFiles, f)
+ }
+ sort.Slice(usedFiles, func(i, j int) bool { return usedFiles[i] < usedFiles[j] })
+ for _, f := range usedFiles {
+ if filesym := ctxt.Lookup(files[f]); filesym != nil {
+ fn(fsym, filesym)
+ }
+ }
+ for _, call := range pc.InlTree.nodes {
+ if call.Func != nil {
+ fn(fsym, call.Func)
+ }
+ f, _ := linkgetlineFromPos(ctxt, call.Pos)
+ if filesym := ctxt.Lookup(f); filesym != nil {
+ fn(fsym, filesym)
+ }
+ }
+
+ dwsyms := []*LSym{fninfo.dwarfRangesSym, fninfo.dwarfLocSym, fninfo.dwarfDebugLinesSym, fninfo.dwarfInfoSym}
+ for _, dws := range dwsyms {
+ if dws == nil || dws.Size == 0 {
+ continue
+ }
+ fn(fsym, dws)
+ if flag&traverseRefs != 0 {
+ for _, r := range dws.R {
+ if r.Sym != nil {
+ fn(dws, r.Sym)
+ }
+ }
+ }
+ }
+}
+
+// Traverse aux symbols, calling fn for each sym/aux pair.
+func (ctxt *Link) traverseAuxSyms(flag traverseFlag, fn func(parent *LSym, aux *LSym)) {
+ lists := [][]*LSym{ctxt.Text, ctxt.Data, ctxt.ABIAliases}
+ for _, list := range lists {
+ for _, s := range list {
+ if s.Gotype != nil {
+ if flag&traverseDefs != 0 {
+ fn(s, s.Gotype)
+ }
+ }
+ if s.Type != objabi.STEXT {
+ continue
+ }
+ ctxt.traverseFuncAux(flag, s, fn)
+ }
+ }
+}
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